(a) The Field of the Invention
This invention relates, in general, to the construction of wood shearing machines and, in particular, to a new and useful wood shearing machine in which a plate holding unit is movable relatively to a wood stock holder for the purpose of cutting a veneer sheet from the wood stock in a manner deflect it into a path so that its edges are turned downward for facilitating the conveying away of the sheets.
(B) The prior Art
Such an embodiment is a considerable advancement in this field since it enables cutting of the wood stock during its upward stroke (from the bottom to the top-) instead of its downward stroke (from the top to the bottom) as usually happens in vertical or almost vertical wood shearing machines, and therefore enables delivery of the sheets cut arranged with their edges turned downwards.
Such an arrangement of the sheets cut at the outlet of the machine, is very important bacause it enables their automatic transfer to a collecting station or to another machine, without the need to resort to manual operations which are usually necessary if the sheets are upsidedown in coming out of the wood shearing machine, that means with their concave section having the edges turned upwards. This position would not permit piling-up of the sheets because it is possible to put them superimposed on top of each other in a stable equilibrium forming piles reaching even half a meter height, only if the sheets have their edges turned downwards.
However, if the sheets have the edges turned upwards, they are subject to rolling up, particularly if the type of wood is hard or its thickness is small, whereby they have to be subjected to various operations; namely, "un-rolling" them turning them upside down and piling them up by keeping them taut; all these operations being by necessity manual operations usually performed in vertical wood shearing machines by three or more operators.
As a person skilled in the art will readily understand, if it is possible to avoid said manual operations this means having a machine capable of a much higher production yield than the machines of the prior art and consequently the sheets cut by means of this machine are obtained at a lower cost.
Moreover, it has to be stressed that the manual "unrolling" of sheets leads to numerous breakages of said sheets caused by the actual impossibility that the three or four operators handling the sheets can act simultaneously and in a time even less than a second, which would be indispensable in order not to damage the sheets which are always very brittle due to their reduced thickness.